1

im using indy10 for my communications, and sometimes when a client disconnects it raises an exception, i was wondering whats the safest way to disconnect a connection (TIdContext) ?

and what should i do on the OnDisconnect even and similar?

thanks.

RRUZ
  • 134,889
  • 20
  • 356
  • 483
killercode
  • 1,666
  • 5
  • 29
  • 42

2 Answers2

3

Raising an exception is normal behavior. Indy is designed to make heavy use of exceptions, not only for error handling but also for internal notifications and such. OnDisconnect is fired when TIdTCPServer detects that the connection is finished, either because the client disconnected (and TIdTCPServer handled the exception for you) or because an uncaught exception occured in your OnExecute handler code. Either way, use OnDisconnect to perform any cleanup you need. TIdTCPServer will close the socket for you after the OnDisconnect event handler exits.

Remy Lebeau
  • 555,201
  • 31
  • 458
  • 770
  • ok, and if i want to close the whole socket? should i just do TIdTCPServer.Active := False? or there is some cleaning up i should do? thanks – killercode Feb 19 '11 at 08:33
  • What "whole socket" are you referring to exactly? A single client, or the entire server? If you want to disconnect individual clients, then simply call `Disconnect()` on their `TIdTCPConnection` object. Setting `Active := False` deactivates the entire service and automatically disconnects any connected clients. `OnDisconnect` will still be fired in both situations. – Remy Lebeau Feb 22 '11 at 08:39
0

I just want to add something about sockets internal work (TCP) that I know:

All that server and client does, they sends pieces of data to each other. Server differs from the client only so that he is passive until any client don't send a connection request first. But if client want or forced to break the connection, all is need to do is stop send data to server. To gracefully close a connection client may send special data about this event, like saying "goodbay" by phone, but this is not absolutely required. Simply imagine phone call from you (client) to any service (server). You start conversation with "hello" and service worker responds. If you accidently press reset on your phone, call will lost. But service still continue his work. And you may make call it again. Nothing bad happens from that.

All what you need to care about is stable and correct client and server work by itself. Check incorrect sending and receiving data. Try to reconnect when it needed from client. If some exception throws inside client it must be processed as needed and its normal situation when current connection was lost by such forced events.

Everything else has already answered by Remy Lebeau.

Dima Zorin
  • 80
  • 2
  • 8